How this calculator works
The signed difference is divided by the original value. A positive result is an increase; a negative result is a decrease. An unchanged value returns zero. The original must be positive to avoid undefined division or ambiguous interpretations of negative baselines.
The formula
Difference = New − Original
Percentage change = Difference / Original × 100.A quick example
Moving from 80 to 100 is an increase of 20, or 25%. Returning from 100 to 80 is a decrease of 20, or −20%, because the base changed.
How to use this calculator
- Enter a positive original value.
- Enter the new value, including a negative value if meaningful for your quantities.
- Calculate signed difference, percentage and direction.
A few common questions
Why do reverse changes have different percentages?
Each direction divides by a different original value.
Why can’t the original value be zero?
Percentage change requires division by the original value. Use an absolute difference instead.
How is this different from percentage difference?
Change uses a directional starting value; difference uses the average of two values as its base.